Magnetically biased telephone ringer



y 1945' L. w. CARROLL 2,380,293

4 MAGNETICALLY BIASED TELEPHONE RINGER Filed Aug. 4, 1942 PERMANENT 1m GNET INVENTOR Lou/.5 W. Cmkau ATTORNEY Patented July 10, 1945 MAGNETICALLY BIASED TELEPHONE BIN GER Louis W. Carroll, New York, N. Y., assignor to In- I ternational Standard Electric Corporation, New

York, N. Y., a corporation of Delaware Application August 4, 1942, Serial No. 453,516

3 Claims. (Cl. 177-7) This invention relates to new and useful improvements in ringers and more particularly in biased electro-magnetic ringers such as are used on telephone party lines where it is required to ring a station only when current flows in the circuit in a given direction. I

The object of the invention is to eliminate the customary adjustable springs or other'mechanical means for securing biased operation.

I shall describe a preferred embodiment of the invention in connection with the drawing which represents the improved ringer in side elevation.

I and l are the customary two electro-magnets having pole pieces and coils supported by a yoke 2. A permanent magnet 3 is fastened to the yoke 2 centrally between the two magnets. The longitudinal axis of the permanent magnet 3 is at the center of yoke 2 midway between the longitudinal axes of the two electro-magnets. The pole at the upper free end of the permanent magnet 3 projects to a point above the pole pieces of the two electro-magnets. By means of rivets 6, a

- fork 5 having two bearing or pivot points 4 (only one being shown) is fastened to the side of magnet 3. The bearing points 4 are to the right of the central axis of the electro-magnet structure and almost in line with the edge of the coil of coils will cause the armature to oscillate and the clapper-arm 1 to hit the gongs ll.

What I claim is:

1. In a biased electro-magnetic ringer, two

electro-magnets, a permanent magnet, means for supporting the magnets, an armature cooperating with said magnets and having its centeraligned with the permanent magnet and adjacent to one pole thereof a magnetic connection between the other pole and said electro-magnets, a pivotal mounting for said armature engaging it at a'point between its center and one end, and a clapperarm attached to the armature at its center.

2. In a biased electro-magnetic ringer, two like I electro-magnets having coils and pole pieces, a yoke on which said magnets are mounted spaced from one another, a permanent magnet of the it its center and one end, and a clapper-arm atstructure and, therefore, its pivot point is to the i right of its center which is in alignment with the permanent magnet 3 and where a clapper arm I is attached. The armature is provided with the usual stop pin 9 near one end cooperating with the pole piece of magnet land an adjustable stop screw at the other end cooper-' customarily produced by a biasing 'springor the tache'dto the armature at its center.

3. In a biasedelectro-magnetic ringer, two like electro-magnets having coils and projecting pole pieces, a yoke on which said magnets are mounted spaced from one another, a permanent magnet of the bar type, one pole of which is attached to said yokecentrally between the coils of said magnets and the other pole of which projects magnets, an armature above the last mentioned poles and in cooperative relationship therewith,

like and holds the magnet armature in the position desired until it is overcome by current through the coil of magnet l' in the proper directhe center of the armature being aligned with the permanent magnet and the ends with the said two electro-magnets, a pivotal support for said armature fastened to the side of the permanent magnet near the free pole thereof and engaging the armature at a point between its center and one'end, a stop pin near one end of the armature cooperating with the pole piece of one electromagnet, an adjustable stop screw near the other end of thearmature cooperating with'the pole pieceof the other electro-magnet, and a clapperarmattached to the armature'at its center.

Louis-w. CARROLL. 

